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NEET2008PhysicsThermal Properties of MatterActual

An electric kettle takes 4 ~A current at 220 ~V . How much time will it take to boil 1 ~kg of water from temperature 20^ C ? The temperature of boiling water is 100^ C

Options

  1. A6.3 ~min
  2. B8.4 ~min
  3. C12.6 ~min
  4. D4.2 ~min

Correct answer

A. 6.3 ~min

Step-by-step solution

Key Idea : Heat eyolved due to Joule's effect is used up in boiling water. As per key idea aligned V I t & =m s t or t & = m s t V aligned Putting under given values gathered I=4 ~A , V=220 volt , m=1 ~kg , t=(100-20)^ C , s=4200 ~J / kg ^ C t= 1 4200 80 220 4 =6.3 ~min gathered

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